Fast food companies have scrambled to limit the fallout from the scandal, and many have ended their contracts with OSI.

McDonald's, which initially stood by the company, has since suspended sourcing products from OSI plants. A company spokeswoman said Tuesday that McDonald's could revisit the decision when the government investigation is complete.

"These events triggered extensive news coverage in China that has shaken consumer confidence, impacted brand usage, and disparaged the hard work of our over 400,000 Chinese employees," the company said late last month in a regulatory filing.

McDonald's Japanese unit also expects sales to suffer, and has published its supplier list to help assure customers that its offerings are safe.